Looking beyond the normal "mechanical" time travel, i.e. jump in a machine or device that transports you forward or backward in time. Could be an interesting take on physics, or a different way of understanding the concept of time.

Two examples that I've seen in past threads:

Verkisto wrote:

]My favorite concept of time travel, in respect to how it affects past and present events, is in To Say Nothing of the Dog by Connie Willis. In that book, people can travel back in time, but the timestream will adjust your arrival time and place based on how your arrival at the programmed time and/or place could affect past or future events.

Sky Knight X wrote:

My favorite time travel book is by Kurt Vonnegut called Timequake. It has an interesting slant on time travel:

The world is flung back 10 years in time. Everyone retains their memories of those 10 years, but must relive everything that happened over that time, fully aware of what is happening.

The most baffling book about time travel I read is Philip K. Dick's "Counter-clock world". While it isn't the traditional way of time travel per se, it is about time turning around at some point and starting to flow backwards: people start their lives at old age, and become younger, back to the days of their youth, until they crawl back into the womb of their mother. The interesting bit is that people's memory is still flowing forward, i.e., they now actually know their future because it is their past.

The movie Source Code has a play on time travel that I think is a slight bit off of the norm (if such a thing exists). It's light entertainment and not likely to spark much 'what if' thinking unless you take some time to ponder what is happening in the bigger picture of the movie.

The problem with making good movies or writing books about time is that our own understanding of time is so absurdly poor. I tend to enjoy the scientific & philosophic writings on time. In some cases, they read much like Sci-Fi / Fantasy.

The short story [url=http://en.wikipedia.org/wiki/Paycheck_(short_story)]Paycheck[/url], also by Philip K. Dick, is good, too.

Odd tangent: I had dinner with a gentleman who spent time with PKD as a kid because his mom dated him and didn't know who he was until he discovered Blade Runner was based on a book his almost-a-stepdad had written.

In Star Trek, the timeline is simply a string of possibilities and there are an infinite number of timelines besides the one you happen to be on. For example, there's an alternate timeline out there where I did not post this, or where Disney did not buy Star Wars.

Whenever you go back and forth in time, you create, essentially an alternate timeline split off from that point, where you can cause things to happen differently. They still happen the same way in that other timeline you came from, but in this new one you created, thinks happen differently.

It is theoretically possible to jump back and forth between different timelines.

Star Trek uses this model, as does Stargate and Sliders.

Basically, anything that CAN happen, has happened, or will happen, just in another timeline (or alternate reality).

Stephen Hawking has suggested that the absence of tourists from the future is an argument against the existence of time travel.

Of course this would not prove that time travel is physically impossible, since it might be that time travel is physically possible but that it is never developed (or is cautiously never used); and even if it is developed, Hawking notes elsewhere that time travel might only be possible in a region of spacetime that is warped in the correct way, and that if we cannot create such a region until the future, then time travelers would not be able to travel back before that date, so "This picture would explain why we haven't been overrun by tourists from the future."

Carl Sagan also once suggested the possibility that time travelers could be here, but are disguising their existence or are not recognized as time travelers.

Alan Lightman's Einstein's Dreams is a fascinating look at different ways to look at time. It's not a novel, but more a collection of vignettes based around a similar theme. It's also über-short, so you could knock it out in a couple of hours at most.

Phillip Jose Farmer's short story "Sketches among the Ruins of my Mind":: An alien probe orbiting Earth causes, every 24 hours, everyone on Earth to fall unconscious. While unconscious, everyone's mind is scanned of all the information and sensory input from the previous 24 hours. The problem is that it has the side effect of erasing the previous 3 days of memory. So everyone is aging 1 day physically, but regressing 3 days mentally.

Sorry, no idea. I've heard of the movie, but don't know anything about it.

Per wikipedia because lord knows I can't explain it on my own...

The book explains that rarely and for unknown reasons, the "Fourth Dimension of Time" becomes corrupted and creates a copy of the universe known as a "Tangent Universe". This universe is connected to the "Primary Universe" by a "Tangential Vortex" (a portal made of water) and is a perfect copy of it and all it contains, except it also contains one duplicated metal object known as an "Artifact". A Tangent Universe is unstable and, unless it is properly collapsed, will collapse itself into a black hole after several weeks, destroying the connected Primary Universe with it.[9]The Tangent Universe is properly collapsed by sending the Artifact through the Tangential Vortex, back to the Primary Universe. This duty falls on one individual, known as the Living Receiver. It is unknown how or why a Living Receiver is chosen. This person acquires "Fourth Dimensional powers", including increased strength, telekinesis, mind control and the ability to conjure fire and water. The Living Receiver is often plagued by disturbing visions and dreams while in the Tangent Universe.[9]All those in the vicinity of the Vortex become "Manipulated Living" and are unconsciously motivated to assist the Receiver in returning the Artifact, through behaviour that may seem bizarre to them. The Manipulated Living will do anything to prevent the destruction of the Primary Universe, though they are not consciously aware of the threat.[9]Those who die within the Tangent Universe become "Manipulated Dead". They are then able to travel through time (using water, the "Fourth Dimensional Construct") to assist the Receiver. The Manipulated Dead enact elaborate plans known as "Ensurance Traps" which, if successful, leave the Receiver no choice but to use his powers to return the Artifact.[9]After the Artifact is returned, the Tangent Universe ceases to exist. In the Primary Universe, those who were Manipulated are often haunted by the experience in their dreams. Many will remember nothing in waking life. Some will become profoundly regretful of their actions in the Tangent Universe. The Artifact will be held in reverence by those in the Primary Universe, as its appearance defies rational explanation.[

My favorite time travel tale is My Name Is Legion by Lester del Rey, a short story from 1942. It uses object duplication, but the difference is that the object is pulled out of its own future and brought back to the present day. And the twist in this story is that the "object" in question is Adolf Hitler. It's a diabolical little tale that I absolutely love.